In order to provide a concrete block in which partially brittle spots rarely appear, which is not costly to manufacture and the structure of which is not costly to construct due to having a simple structure, and in which is formed a joint that bears shear stress in the horizontal direction in-plane of a face shell and in a horizontal direction orthogonal to the aforementioned horizontal direction, the present invention is structured such that joints 11a, 12a that bear shear stress in the horizontal direction in-plane of the face shell are configured from from a trapezoidal crest part formed on one side of a face shell 1, the crest part having a horizontal portion on both sides, and a trapezoidal trough part formed on a side 12 that is parallel to the side 11, the trough part having a horizontal portion on both sides.